V8 | martinuke0's Blog

Abstract visualization of a JIT compiler pipeline transforming bytecode into optimized machine code

Inside V8's TurboFan's Maglev: How Speculative JIT Compilation Powers Modern JavaScript

Maglev is V8’s mid-tier JIT compiler sitting between Sparkplug and TurboFan. It uses speculative type feedback and SSA-based IR to compile hot functions quickly while preserving most of TurboFan’s optimization headroom.

Diagram of V8's TurboFan pipeline showing bytecode, IR graphs, and machine code stages.

Inside V8's TurboFan Optimizing Pipeline: Tracing JIT Compilation from Bytecode to Machine Code

Trace a JavaScript function from parsed bytecode all the way through TurboFan’s Sea of Nodes IR, speculative optimizations, and final machine code emission, with the concrete phase ordering V8 actually uses.

Abstract illustration of a compiler pipeline transforming nodes into optimized machine code.

Inside the V8 TurboFan Compiler: How Speculative JIT Compilation Really Works

How TurboFan turns hot JavaScript into optimized machine code using speculation, Sea of Nodes IR, and feedback-driven inlining — and why it has to bail out so often.